1. Field of the Invention
The present invention relates to a valve timing control device and, in particular, to the valve timing control device for controlling an angular phase difference between a crankshaft of a combustion engine and a camshaft of the combustion engine.
2. Conventional Technology
A conventional valve timing control device comprises: a rotary member rotates with a crankshaft of an internal combustion; a rotational transmitting member rotates with a camshaft; a vane provided on the rotary member; and a pressure chamber formed between the rotary member and the rotational transmitting member, and divided into an advancing chamber and a delaying chamber by the vane. The rotational transmitting member has a cylindrical housing member mounted around the peripheral surface of the rotary member, and two circle plate members fixed on ends of the cylindrical housing member and a timing sprocket connected to a crankshaft by a timing chain. Such a conventional variable timing device is disclosed, for example, in Japanese Patent Laid-Open Publication No. H(Heisei) 10-141022.
In the conventional valve timing control device, the valve timing is advanced due to relative displacement between the rotary member and the rotational transmitting member the fluid is supplied to the advancing chamber and is discharged from the delaying chamber. On the contrary, the valve timing is delayed due to the counter displacement between the rotary member and the rotational transmitting member when the fluid is discharged from the delaying chamber and is supplied to the delaying chamber.
Further, in the conventional valve timing control device disclosed in the publications, there are predetermined gaps between the outside surfaces of the cylindrical housing member and the inside surfaces of each of the plate member. The gaps are filled up with a small amount of the fluid that is leaked from the advancing chamber and/or the delaying chamber so as to make fluid slicks. Therefore, the operation of the conventional valve timing control device quickens.
However, even if the rotational phase (the angular phase difference) between the crankshaft and the camshaft is fixed on the internal combustion engine driving, the camshaft receives variational torque so that the rotary member continuously rotates relative to the rotational transmitting member within a small range. At the time, as loads of the gaps to maintain the fluid slicks become large, it is difficult to keep the small amount of the fluid in the gaps.
In addition, here exists some risk that the tension of the timing chain, which connects between the crankshaft and the timing sprocket, may make one of the gaps small. As a result, the fluid slick between one of the outside surfaces of the cylindrical housing member and the inside surface of the plate member may disappear such that the internal opposition increases.
The invention has been conceived to solve the above-specified problems. According to the invention, there is provided a valve timing control device comprising: a rotary member that rotates with one of a crankshaft of an internal combustion engine or a camshaft thereof; a rotational transmitting member that rotates with the other of the camshaft or the crankshaft, and which has a cylindrical housing portion mounted around the peripheral surface of the rotary member and a circle plate portion fixed on one end of the cylindrical housing portion and slidably contacted with one end of the rotary member; a vane provided on the rotary member; a pressure chamber formed between the rotary member and the rotational transmitting member, and divided into an advancing chamber and a delaying chamber by the vane; and an oil retainer disposed between the circle plate portion of the rotational transmitting member and the rotary member.
Other objects and advantages of invention will become apparent during the following discussion of the accompanying drawings.